PPIB and melanoma: In this study, we were able to show that all but one selected (tested) protein kinases inhibitors: PI3K (LY294002), ERK1/2 (U0126), mTOR (rapamycin and everolimus), B-RAF (GDC-0879), and GSK-3β (CHIR-99021) used individually or in combination had strong anti-proliferative effect on melanoma cell lines.